SAN FRANCISCO -- Major League Baseball's ongoing support of the Athletics' effort to build a new stadium remains a top priority for Commissioner Rob Manfred.

Speaking with reporters before Game 3 of the National League Division Series on Monday night (airing on FS1; Cubs lead, 2-0), Manfred said that he has spent more time working on the A's stadium situation that any other issue related to one franchise in his nearly two years as Commissioner. He was wearing a smile when he arrived to the news conference at AT&T Park.

"Well, this trip to San Francisco's now officially worthwhile,'' Manfred said. "I just got to spend five minutes with Willie Mays, so the rest of it is all gravy.''

MLB has been supporting the work of the owners of the A's and Tampa Bay Rays on stadium efforts for years. Manfred has said that MLB is open to considering expansion but won't pursue it until resolving those two teams' stadium situations.

Oakland's effort is affected by the fact that the A's share the Coliseum with the NFL's Raiders, who are also seeking a new stadium.

Manfred reaffirmed MLB's desire for the A's to find a new stadium in Oakland instead of another location in the Bay Area. Manfred said he has been engaged in dialogue with Oakland Mayor Libby Schaaf about a variety of possibilities.

"I am hopeful that in relatively short order we will start to have news about how this is going to proceed,'' Manfred said. "I talked to the mayor of Oakland last week. She seems very committed to the idea of keeping baseball in Oakland. That's a huge positive for us.''

Manfred told reporters that Schaaf told him "repeatedly'' she'd prefer baseball over football if the market could support only one new stadium.

"I know that the one thing I will say to you is the mayor in Oakland has made clear to me that baseball is her first priority,'' Manfred said. "She would like to keep both teams, but baseball is her first priority. And I think that's a good spot for baseball to be in.''

Manfred indicated that the next step in the process is for the A's and the City of Oakland to settle on a site. The leading site possibilities have been the area adjacent to the Coliseum and Howard Terminal.

"There are actually others, and I hope the first piece of news will be a decision as to which site will be the focus of their effort to get their plan and financing together,'' Manfred said. "I hope in the next year we will have a good idea about how the project's going to proceed.''

Manfred acknowledged that the shared-stadium factor and the fact that a plan for financing is in the earliest stages make Oakland's situation "complicated." He added, however, that MLB maintains a sense of urgency and supports the franchise's efforts as its stadium push moves ahead.

"We will stay engaged with the A's," Manfred said. " The A's project is a project that will involve a very substantial commitment from local ownership. And, as a result of that, it has to be a locally driven project. They need to find a project that they think works for them, and they need to push that project forward.

"We will continue to impress upon them the urgency of getting a Major League-quality facility in Oakland, and we will continue to provide them with support as they move through the process."

On other topics, Manfred said:

• Negotiations toward the next Collective Bargaining Agreement (the current one runs through Dec. 1) have reached a stage where Manfred is sitting in on some meetings. It's uncertain, however, whether a deal can be agreed upon by the end of the World Series.

Manfred shares progress on CBA

Commissioner Manfred discusses CBA negotiations

Commissioner Rob Manfred offers an update on negotiations for the Collective Bargaining Agreement

"I have said, in terms of timing, various things, but I am optimistic we'll have a deal this fall,'' Manfred said. "I remain optimistic about that. I think there are some natural deadlines out there. The beginning of the free-agency period and the expiration of the agreement on December 1. I'm hopeful that we'll be able to get an agreement in advance of those natural deadlines.''

• A recent report that a reduction of the regular-season schedule from 162 games to 154 games is being discussed was inaccurate.

"Yeah, the writer took that incorrectly,'' Manfred said, declining to discuss specifics of the negotiations. It's likely that the scheduling issues being discussed are matters involving game times and off-days.

• MLB hopes to have streaming of local games available in all 30 markets next season. The league negotiated a lifting of blackouts with teams carried by FOX for this season and has remained in talks with other Regional Sports Networks.

• It's unlikely that MLB will expand the list of plays that can be electronically reviewed via the replay system to include checked swings.

Manfred on replay rulings

Rob Manfred talks about correct calls based on replay

Commissioner Rob Manfred talks about the importance of making the correct call based on replay review and how to improve the system

"With respect to checked swings, our concept on replay -- and you need a concept in order to design a system -- has been that we wanted to review and get right impactful plays in a game,'' Manfred said. "I think that the vast majority of the time, a checked-swing call is not really an impactful play in the game, and that the additional delay that could take place as a result of adding that type of play to the replay process probably isn't worth it, in my mind. ... Balls and strikes is a whole additional sort of line in the sand that we have been reluctant to cross.''

Phil Rogers is a columnist for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.